Portland, Ore.

New intrauterine device has fewer side effects and is close to 100 percent effective

A new contraceptive that takes just minutes to place and guarantees almost 100 percent pregnancy protection for five years now is available at Oregon Health Sciences University. Mirena, a hormone releasing intrauterine device, was approved by the U.S. Food and Drug Administration earlier this year, and was just released to clinics last week.

OHSU and about 20 other sites were chosen to participate in an American clinical trial of Mirena. The clinical trial looks at women who previously have delivered a child and are interested in a long-acting method of contraception to determine how women adapt to Mirena. The study also will expose the device to a group of clinicians who can then train other health care providers. As a result of participating in this study, OHSU is one of the first institutions in Oregon to offer Mirena as a contraceptive option.

"Mirena requires no daily pill or interruption to sexual activity," said Sandra Emmons, M.D., assistant professor of obstetrics and gynecology, OHSU School of Medicine, and co-investigator in a trial study of Mirena. "It requires no daily thought and is easily reversible."

Mirena is a thin, T-shaped piece of plastic that is inserted in the uterus. The insertion takes just a few minutes and is done in a physician's office. The IUD delivers a low dose of progesterone inside the uterus. The progesterone blocks sperm movement and thins the uterine lining, but causes very few systemic side effects. The blood level of progesterone in a woman using Mirena is 100 times less than that of a woman on birth control pills.

"One advantage of Mirena over current methods of birth control is that the local dose of progesterone markedly reduces menstrual bleeding and cramping," said Emmons. "Heavy menstrual bleeding and cramping is experienced by 5-10 percent of women while using non-progesterone IUDs. In fact, Mirena can be used to treat women who suffer from heavy menses or menstrual cramping."

Women return to normal fertility as soon as Mirena is removed. "An IUD can be an ideal method for a woman who has completed her childbearing and is in a monogamous relationship," said Jeffrey Jensen, M.D., M.P.H., associate professor of obstetrics and gynecology, OHSU School of Medicine, and co-investigator in a trial study of Mirena.

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